1. Field of the Disclosure
The present disclosure relates to an input device of an information device such as a computer or smartphone or the like and an information input method of the same, and more particularly relates to an input device which identifies a region on an operating face where an object such as a finger or pen has come into contact or into proximity, and inputs information based on the identified region.
2. Description of the Related Art
Devices such as touch pads and touch panels have come into widespread used as input interfaces of information equipment such as laptop personal computers (PCs), tablet terminals, smartphones, and so forth. These devices have sensors to detect contact positions of objects such as a finger or a pen. There are various types of sensors, which detect contact positions of objects, such as resistive film and capacitive types. Recently, there has been increased use of capacitive sensors, which are capable of handling so called “multi-touch”, where multiple contact positions are detected.
Common capacitive sensors have multiple electrodes arrayed in a grid pattern, and detect capacitance between electrodes (mutual capacitance) and capacitance between electrodes and a ground (self capacitance). An input device described in Japanese Unexamined Patent Application Publication No. 2012-43395 has multiple X electrodes and multiple Y electrodes arrayed in a grid pattern (FIGS. 1 and 2), with capacitance being detected at positions corresponding to each grid intersection point. One of the X electrodes and Y electrodes is used as driving electrodes, and the other as receiving electrodes. Mutual capacitance at points where the receiving electrodes and driving electrodes intersect is detected in accordance with current flowing through the receiving electrodes when driving pulses are applied to the driving electrodes.
The input device described in Japanese Unexamined Patent Application Publication No. 2012-43395 yields capacitance detection data at each intersection of the X electrodes and Y electrodes arrayed in the grid pattern. Collecting the detection data from each intersection forms two-dimensional data representing the capacitance at each position on the operating face. Information of finger contact positions on the operating face is obtained based on this two-dimensional data. This is performed by scanning the detection data of the two-dimensional data one line at a time, in the horizontal direction, from the bottom to the top. A region where the detection data indicating contact by the finger is consecutive is given the same label in the scanning of each line. This scanning is performed for horizontal lines, in a direction from the bottom to the top and in the opposite direction, and moreover, such scanning is performed for the vertical lines from the left edge to the right edge, and in the opposite direction.
However, this method of scanning the two-dimensional data several times necessitates a broad range of scan history to be stored, which is problematic in that the memory capacity required for this is great, and that the computation load also is great.